were returned, either the trait or the *self type itself*, were not
particularly representative of what the Def is (a type parameter).
Rewrite paths to handle this case specially, just as they handle the
primitive case specifically. This entire `def_id` codepath is kind of a
mess.
this simplifies the code while reducing the size of libcore.rlib by
3.3 MiB (~1M of which is bloat a separate patch of mine removes
too), while reducing rustc memory usage on small crates by 18MiB.
This also simplifies the code considerably.
I have measured a small, but possibly insignificant, bootstrap performance improvement, and the memory savings grow to about 30M for larger crates (but that is still less as a percentage).
r? @eddyb
This commit swaps the order of linking local native libraries and upstream
native libraries on the linker command line. Detail of bugs this can cause can
be found in #28595, and this change also invalidates the test case that was
added for #12446 which is now considered a bug because the downstream dependency
would need to declare that it depends on the native library somehow.
Closes#28595
this simplifies the code while reducing the size of libcore.rlib by
3.3 MiB (~1M of which is bloat a separate patch of mine removes
too), while reducing rustc memory usage on small crates by 18MiB.
This also simplifies the code considerably.
By putting an "unreachable" instruction into the default arm of a switch
instruction we can let LLVM know that the match is exhaustive, allowing
for better optimizations.
For example, this match:
```rust
pub enum Enum {
One,
Two,
Three,
}
impl Enum {
pub fn get_disc(self) -> u8 {
match self {
Enum::One => 0,
Enum::Two => 1,
Enum::Three => 2,
}
}
}
```
Currently compiles to this on x86_64:
```asm
.cfi_startproc
movzbl %dil, %ecx
cmpl $1, %ecx
setne %al
testb %cl, %cl
je .LBB0_2
incb %al
movb %al, %dil
.LBB0_2:
movb %dil, %al
retq
.Lfunc_end0:
```
But with this change we get:
```asm
.cfi_startproc
movb %dil, %al
retq
.Lfunc_end0:
```
As discussed in the referenced issues, this PR makes rustc emit `__imp_<symbol>` stubs for all public static data to ensure smooth linking in on `-windows-msvc` targets.
Resolves#26591, cc #27438
This PR removes random remaining `Ident`s outside of libsyntax and performs general cleanup
In particular, interfaces of `Name` and `Ident` are tidied up, `Name`s and `Ident`s being small `Copy` aggregates are always passed to functions by value, and `Ident`s are never used as keys in maps, because `Ident` comparisons are tricky.
Although this PR closes https://github.com/rust-lang/rust/issues/6993 there's still work related to it:
- `Name` can be made `NonZero` to compress numerous `Option<Name>`s and `Option<Ident>`s but it requires const unsafe functions.
- Implementation of `PartialEq` on `Ident` should be eliminated and replaced with explicit hygienic, non-hygienic or member-wise comparisons.
- Finally, large parts of AST can potentially be converted to `Name`s in the same way as HIR to clearly separate identifiers used in hygienic and non-hygienic contexts.
r? @nrc
By putting an "unreachable" instruction into the default arm of a switch
instruction we can let LLVM know that the match is exhaustive, allowing
for better optimizations.
For example, this match:
```rust
pub enum Enum {
One,
Two,
Three,
}
impl Enum {
pub fn get_disc(self) -> u8 {
match self {
Enum::One => 0,
Enum::Two => 1,
Enum::Three => 2,
}
}
}
```
Currently compiles to this on x86_64:
```asm
.cfi_startproc
movzbl %dil, %ecx
cmpl $1, %ecx
setne %al
testb %cl, %cl
je .LBB0_2
incb %al
movb %al, %dil
.LBB0_2:
movb %dil, %al
retq
.Lfunc_end0:
```
But with this change we get:
```asm
.cfi_startproc
movb %dil, %al
retq
.Lfunc_end0:
```
Make sure Name, SyntaxContext and Ident are passed by value
Make sure Idents don't serve as keys (or parts of keys) in maps, Ident comparison is not well defined
This patch basically adds a target option for omitting the `-nodefaultlibs` flag when invoking the linker. I am not sure if this is the correct or only way to approach this problem, so any feedback is welcome.
Motivation: I'm currently working on a Rust target specification for the [rumprun](/rumpkernel/rumprun) unikernel. rumprun is based on rump kernels and uses NetBSDs libc and drivers to provide a POSIXy environment. It provides its own linker wrapper that generates binaries which can be "baked" into a unikernel after configuration. Using `-nodefaultlibs` on the rumprun linker will prevent it from selecting the search paths for the rumprun libraries. My current target implementation for rumprun is here: gandro/rust@295744b2ee
Currently, only a target that `is_like_windows` will omit the `-nodefaultlibs` flag, but since rumprun is not like Windows otherwise, I think a separate flag makes more sense. This might be a breaking change for target specifications that have the `is_like_windows` option set to true. Such targets need to set `no_default_libraries` to false in order to restore the old behavior.
If set to false, `-nodefaultlibs` is not passed to the linker. This
was the default behavior on Windows, but it should be configurable
per target.
This is a [breaking-change] for target specifications that have
the `is_like_windows` option set to true. Such targets need to
set `no_default_libraries` to false in order to restore the old
behavior.
Should be lowering ast expressions to HIR expressions, not cheating via the hir map. That goes wrong now that there is not a 1:1 mapping between ast and hir (in the case of the crash due to ExprParen).
Should be lowering ast expressions to HIR expressions, not cheating via the hir map. That goes wrong now that there is not a 1:1 mapping between ast and hir (in the case of the crash due to ExprParen).
